package com.example;


import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;
 
public class App {
 
	//自定义Mapper类
	public static class MyMapper extends Mapper<Object, Text, Text, Text>{
		
		// 新建Text类型对象，用来存放科目
		private Text text = new Text();
		 
		
		public void map(Object key, Text value, Context context) throws IOException, InterruptedException {
			 text = value;
			 context.write(text, new Text(""));
		} 
	}
	
	// 自定义Reducer类
	 
	public static class MyReducer extends Reducer<Text, Text, Text, Text> {
		 
		
		public void reduce(Text key, Iterable<Text> values, Context context) throws IOException, InterruptedException {
			 context.write(key, new Text(""));
			
		}
		
	}
	
	
	public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
		
		Configuration conf = new Configuration();
		String[] otherArgs = (new GenericOptionsParser(conf,args)).getRemainingArgs();
		if(otherArgs.length<2){
			System.err.println("Usage:CrossTest <in> [..<in>] <out>");
			System.exit(2);
		}
		
		Job job = Job.getInstance(conf,"the homework5 of ZZB");
		job.setJarByClass(App.class);
		job.setMapperClass(MyMapper.class);
		job.setReducerClass(MyReducer.class);
		job.setMapOutputKeyClass(Text.class);
		job.setMapOutputValueClass(Text.class);
		job.setOutputKeyClass(Text.class);
		job.setOutputValueClass(Text.class);
		 
		for(int i = 0; i <otherArgs.length - 1;i++){
			FileInputFormat.addInputPath(job,new Path(otherArgs[i]));
		}
		FileOutputFormat.setOutputPath(job,new Path(otherArgs[otherArgs.length -1]));
	 
		System.exit(job.waitForCompletion(true) ? 0 : 1);
		
		
	}
}
